Acid nickel electroplating baths and processes



United States Patent 3,282,811 AClD NICKEL ELECTROPLATING RATES AND PROCESSES Wennemar Strauss, Dnsseldorf-Holthausen, and Alfred Kirstahier, Dusseldorf, Germany, assiguors to Dehydag Deutsche Hydrierwerke G.m.b.l-l., Dusseldorf, Germany, a corporation of Germany No Drawing. Filed Nov. 20, 1963, Ser. No. 325,174

Claims priority, application Germany, Dec. 4, 1962,

26 Claims. bi. 204-49 This invention relates to a nickel electroplating method and bath wherein additives are used having brightening and leveling properties. These additives are organic compounds having cyclic quaternary ammonium and sulfonamide, disulfimide or sulfocarbonimide groups.

It is an object of this invention to provide a method bright, level, ductile and adherent electrodeposits of nickel.

These and other objects of our invention will become apparent as the description thereof proceeds.

It has been found that organic compounds which contain at least one cyclic, quaternary ammonium group and at least one sulfonamide, disulfimide or sulfocarbonimide group in the molecule, exhibit excellent brightening and leveling properties in acid nickel electroplating baths.

It is already known to use diaryl-disulfimides or halosubstituted diaryl-disulfimides as brightening agents in nickel electroplating baths. In addition, sulfoca-rbonimides have already been used as brightening agents in nickel electroplating baths. Finally, the inner salts of pyridine alkane sulfonic acids have also been used as leveling agents in acid nickel electroplating baths. However, all of these products have the disadvantage that optimum effects can be achieved with them only in combination with other additives, such as brightening, leveling, pore-prevention and wetting agents.

When the agents according to the present invention are used, only the addition of wetting agents is necessary in order to achieve high performance baths which fulfill all the requirements even under the most difiicult conditions. In comparison to known nickel electroplating baths, the baths according to the present invention have the following advantages:

Since they require no further additives other than wetting agents, which necessitate no difficult analytical surveillance, the control of the baths is simple because only one bath component needs to be controlled. The analytical control of the active substances according to the present invention is particularly easy because they exhibit a strong ultra-violet absorption. For their detection under ultra-violet light, the substances do not need to be isolated first by precipitation, extraction or organic solvents or similar manipulations, but instead it suffices to dilute 1 cc. of the bath fluid with water to a volume of 100 cc. and to measure the extinction of this dilute solution.

The baths are substantially more economical than the previous bath combinations because the electrochemical decomposition of the agents used in accordance with the present invention is much less than that of known products. A further advantage of the use of the agents according to the present invention is the easy regeneration property of the bath with the aid of activated charcoal.

. 3,282,811 Patented Nov. 1, 1966 The products used in accordance with the present invention not only produce excellent brightening and leveling etlects, but they are further characterized by an extraordinarily good depth distribution of the brightening and leveling effect, which extends into the area of very low current densities with a temperature tolerance which is suificient for all practical requirements.

The products used in accordance with the present invention are, as described above, characterized by at least one cyclic quaternary ammonia group, which may, for example, be'derived from heterocyclic tertiary bases such as pyridine, quinoline, isoquinoline, pyrimidine, pyrazine, thiazole, etc., and by at least one sulfonamide, disulfimide or sulfocarbonimide group.

These products are obtained by known methods, that is, by reacting such tertiary bases with those sulfonamide, disulfimide or sulfocarbonimide compounds which contain an external exchangeable halogen atom whereby they are capable of undergoing a quaternization reaction.

Accordingly, for example, a compound which is active pursuant to the present invention of the formula is obtained by reacting 1-chloromethyl-benzene-4-sulfamide with an equimolecular arnountof pyridine in an aqueous medium or in excess pyridine at 90 C.

In analogous fashion the compound l F l J: J. TQJJ L Where R R R R =lower alkyl, and when terminal a member selected from the group consisting of lower alkyl and canbonamide groups whereat one or all of these groups may be missed :sulfonamide, disulfimide, sulfocarbonimide groups l l: l cyclic quaternary ammonium group n= to 1, 0:0 to 1 (n and 0 are not simultaneously 0) m=0 to 1, 1:0 to 1, q=0 to 1 (p and q are not simultaneously 0).

The agents according to the present invention are added to the nickel electroplating baths in amounts of 50 mgm. to 5 gm. per liter, preferably in amounts of l00 to 500 mgm./l, of bath fluid. The products may also be used in the electroplating baths in the form of difiicultly soluble, controlled release agents which gradually go into solution or may be inserted into solution filters. In this manner self-regulating baths are provided which require still less surveillance. The high stability of the compounds in the operation of the electroplating baths is particularly advantageous under these conditions.

The following specific examples are presented to illustrate the invention and to enable persons skilled in the art to better understand and practice the invention and are not intended to be limitative.

EXAMPLE I When a nickel bath of the Watts type was modified with 50 to 150 mgm. of the compound of Formula 2 above and 0.1 gm. of sodium dodecylsulfate as a wetting agent, both per liter of bath fluid, ductile, firmly adhering, full bright and satisfactorily leveled nickel electrodeposits were obtained within a current density range of 0.1 to 8 amp./ dm. at 55 C.

EXAMPLE H When a nickel bath of the Watts type was modified with 0.4 gm. of the product of Formula 7 above and with 0.1 gm. of sodium dodecylsulfate as a wetting agent, both per liter of bath fluid, ductile and firmly adhering nickel electrodeposits with a high brightness and good leveling effect were obtained within a current density range of 0.1 to 7 amp./dm. at 53 C.

EXAMPLE III 0.2 to 0.4 gm. of the compound of formula 9 and 0.1 gm. of sodium dodecylsulfate as brightening agent, both perliter of bath fluid, were added to a nickel bath of the @if i il Watts type. The nickel electrodeposits obtained in a current density range of 0.1 to 8 amp./dm. at 55 C. were firmly adhering, ductile, and exhibit an excellent full brightness and strong leveling effect.

EXAMPLE IV A nickel electroplating bath of the Watts type, which contained per liter of bath fluid 0.1 gm. of sodium dodecylsulfate as a wetting agent, was operated with the product of the formula 4 above as a controlled release additive lying on the bottom of the electroplating cell. The bath produced nickel electrodeposits of high brightness and good leveling effects within a current density range of 0.1 to 7 amp/rim. at 55 C.

EXAMPLE V The compound of Formula 6 above was introduced as a controlled release additive into a solution filter of a nickel bath of the Watts type which contained per liter of bath fluid 0.1 gm. of sodium dodecylsulfate as a wetting agent. The bath produced ductile, firmly adhering and satisfactorily bright nickel electrodeposits with a medium leveling effect at 55 C. in a current density range of 0.1 to 4 amp./dm.

EXAMPLE VI A nickel electroplating bath of the Watts type, which contained per liter of bath fluid 0.1 gm. of sodium dodecylsulfate as a wetting agent, was operated with a product of the Formula 5 above as a conrolled release additive lying at the bottom of the electroplating cell. The self-regulating bath produced ductile, firmly adhering, full bright and satisfactory leveled nickel electrodeposits at 60 C. in a current density range of 0.1 to 3 amp./dm. By virtue of the good brightness depth distribution, the bath was particularly suitable for large scale electroplating operations, for instance, by the drum or bell process.

While certain specific examples and preferred modes of practice of the invention have been set forth it will be understood that this is solely for the purpose of illustration and that various changes and modifications may be made without departing from the spirit of the disclosure and the scope of the appended claims.

We claim:

1. A Watts type nickel electroplating bath to which has been added a compound having the general formula where R R R R is lower alkyl, and when terminal a member selected from the group consisting of lower alkyl and carbonamide groups, w'hereat one or all of these groups may be missed, X is a member selected from the group consisting of sulfonamide, disulfamide and sulfocarbonimide groups,

is a cyclic quaternary ammonium group, n is an integer from 0 to 1, o is an integer from 0 to 1, where n and 0 are not simultaneously 0, m is an integer from 0 to l, p is an integer from 0 to l, q is an integer from 0 to l, where p and q are not simultaneously 0, in suflicient quantity to obtain bright, level nickel electrodeposits.

2. The 'bath of claim 1 wherein the additive compound is added in an amount from about 50 mg. to 5 g. per liter of bath.

3. The bath of claim 1 wherein the additive compound is added in an amount from about to 500 mg. per liter of bath.

4. The bath of claim 1 containing in addition Wetting 13. A Watts type nickel electroplating bath to which agents. has been added a compound having the formula 5. A Watts type nickel electroplating bath to which has been added a compound having the formula Q I Q in sufificient quantity to Obtain brighb level nickel electro' in sufiicient quantity to obtain bright, level nickel electrodeposits. deposits. v

A Watts yp nlckel f P bath to Whlch has '14. A method for producing bright, level nickel elecbfiefl added a Compound having the formula trodeposits which comprises forming said electrodeposits r in a Watts type nickel electroplating bath to which has CH SO N-SO CH G 2 G 3 been added a compound having the structural formula 1 PG I r r 1 r N -R XR R X R --N L J. 2 L 3 L J0 L in sufficient quantity to obtain bright, level nickel electrowhere R R R R is lower alkyl, and when, terminal deposits. a member selected from the group consisting of lower 7. A Wat-ts type nickel electroplating bath to which alkyl and carbonamide groups, whereat one or all of has been addedacompound having the formula these groups may be missed, X is.a member selected p from the group consisting of sulfonamide, disulfimide l:SOzNHCH2CHzN\ C1- and sulfocarbonimide groups, OH; I in sufiicient quantity to obtain bright, level nickel electrodeposits.

8. A Watts type nickel electroplating bath to which has is a cyclic quaternary ammonium group, n is a number been added a compound having the formula from 0 to 1, 0 is a number from 0 to 1, Where n and 0 are not simultaneously 0, m is a number from 0 to 1, p is a number from 0 to 1, q is a number from 0 to 1, where p and q are not simultaneously 0, in sufficient quantity to obtain bright, level nickel electrodeposits. 15. The method of claim 14 wherein the quantity of N-CH SO N O Q s 2 the added compound is from about mgm. to about 5 in sufiicient quantity to obtain bright, level nickel electro- P liter of bath- 4() 16. The method of claim 14 wherein the quantity of deposits.

9. A Watts type'nickel electroplating bath to which has e added Compo d is from about 100 mgm. to 500 been added a compound having the formula mgm. per liter of bath.

1-ion SOgI ISOzOH -lq 01- in sufficient quantity to obtain bright, level nickel elec- 17. The method of claim 14 wherein wetting agents trodeposits. are added to the bath.

10. A Watts type nickel electroplating bath to which 18. A method for producing bright, level nickel elechaS been added a C mp und ha g the formula 50 trodeposits which comprises forming said electrodeposits I in a Watts type nickel electroplating bath to which has NoH r been added a compound having the structural formula Q C I: -oni-somm] c1- y SO'N SOZ 19. A method for producing bright, level nickel electrodeposits which comprises forming said electrodeposits in a Watts type nickel electroplating bath to which has in sufficient quantity to obtain bright, level nickel elecbeen added a compound having m6 Structural formula trodeposits.

11. A Watts type nickel electroplating bath to which oH,--so, Nso,--om has been added a compound having the formula 20. A method for producing bright, level nickel elec CHIGONH @SOFN trodeposits which comprises forming said electrodeposits in sufiicient quantity to obtain bright, level nickel electrom a Watts type nickel electrQplatm'g bath to Whlch has deposits, been added a compound havlng the structural formula 12. A Watts type nickel electroplating bath to which has been added a compound having the formula HO P m 1-ioHzs0r-fi-so2om in sufficient quantity to obtain bright, level nickel electro- 21- A method for producing bright, level nickel elecdeposits. trodeposits which comprises forming said electrodeposits in a Watts type nickel electroplating bath to which has been added a compound having the structural formula NC r --S02N-SO2 22. A method for producing bright, level nickel electrodeposits which comprises forming said electrodeposits 10 in a Watts type nickel electroplating bath to which has been added a compound having the structural formula 25. A method for producing bright, level nickel electrodeposits which comprises forming said electrodeposits in 9. Watts type nickel electroplating bath to which has been added a compound having the structural formula 26. A method for producing bright, level nickel electrodeposits which comprises forming said electrodeposits in a Watts type nickel electroplating bath to which has been added a compound having the structural formula 23. A method for producing bright, level nickel electrodeposits which comprises forming said electrodeposits in 21 Watts type nickel electroplating bath to which has been added a compound having the structural formula trodeposits which comprises forming said electrodeposits in a Watts type nickel electroplating bath towhich has been added a compound having the structural formula References Cited by the Examiner UNITED STATES PATENTS 2,644,788 7/ 1953 Shenk 20449 2,644,789 7/ 1953 Shenk 20449 2,658,867 11/1953 Little 20449 2,757,133 7/1956 Shenk 20449 3,023,151 2/1962 Strauss et al. 20449 3,054,733 9/1962 Heil-ing 20449 3,206,383 9/1965 Kappel 20449 FOREIGN PATENTS 610,888 12/1960 Canada.

JOHN H. MACK, Primary Examiner. G. KAPLAN, Assistant Examiner. 

1. A WATTS TYPE NICKEL ELECTROPLATING BATH TO WHICH HAS BEEN ADDED A COMPOUND HAVING THE GENERAL FORMULA 